1. Scope of Invention
This invention relates generally to a method and apparatus for folding a sheet of paper which is continuously moving in a single plane.
2. Prior Art
Heretofore it was necessary to momentarily stop the lateral movement of a sheet of paper in order to form a fold. One common type of folding mechanism is a buckle folder wherein the leading edge of the sheet is fed into a pocket causing the adjacent portion to buckle and to be fed into the bite of adjacent folding rolls. Another type of folder is the blade type when the sheet is passed over a pocket and a blade operates to push a portion of the sheet into the pocket to form a fold. In both prior-known types of folding, the forward or feeding motion of the sheet has to be momentarily stopped while the fold is being formed.
My previous U.S. Pat. No. 4,310,325 provides a method and apparatus for folding a sheet of paper without interrupting the path of movement and the continuous feeding motion of the sheet. This is important to increase the folding speed of the sheets. Each folded portion of the sheet is retained in its folded position while the additional folds are sequentially formed. However, in this previous patent, the speed of this apparatus and method were limited due to the fact that only one sheet would be raised and folded for each revolution of the sheet folding mechanism, it having a pair of spaced apart single excentrically mounted pulleys. Based in part upon other significant improvements by applicant in signature folding sequencing as taught in another of my previous U.S. Pat. No. 5,655,866, a substantially higher sheet folding rate is now a desired feature not offered by current technology.